Airplane-launching appliance



Oct. 22, 19 29.

L. M DONALD AIRPLANE LAUNCHING APPLIANCE Filed July 12. 1928 Fatentecl Oct. 22, 1929 UNITED STATES LESLIE R. MCDONALD, OF MONTREAL, QUEBEC, CANADA AIRPLANE-LAUNCHING APPLIANCE Application filed July 12, 1928.

My invention relates to that class of airplane launching appliances wherein the airplane is suspended and is made to develop suliicient speed to sustain it in flight before being released from the means by which it is suspended; and objects of my improvements are to utilize the force of gravitation in developing a take-off speed in the suspended airplane; to utilize certain novel forms of m suspending and releasing means, both manually and automatically controlled, and to so sustain the airplane that it may be drawn back and allowed to swing downward and forward toward the take-off point and to be released before the speed developed has been materially diminished by any upward swlng of the suspending apparatus or the airplane. These features of my invention will be more fully explained and pointed out hereinan after.

' In the drawings Fig. 1 is an elevation of one form of my improved take-01f apparatus,

showing an airplane suspended thereby; Fig.

2 is a View of the same looking to the left on as Fig. 1; Fig. 3 is a view of the same showing the airplane sling and airplane drawn back to an elevated position, and ready for release; Fig. 4 is a view 011 an enlarged scale of the sling basket and part of the fuselage of the y 39 airplane, looked at from the same position as shown in Fig. 2, part of the basket and of the fuselage being broken away for clearness; Fig. 5 is a plan view of the same, omitting the fuselage; and Fig. 6 is a detail of the air- 55 plane carrying loop on the basket. Similar letters of reference designate s11n1- lar parts in all the figures. Two towers, 1, 2, preferably of steel construction, support a girder 3, from which suitao able cables 4, 5, 6, 7, are stretched to and secured to the corners of the basket 8, which is of sufficient strength and rigidity to carry the weight of an airplane and to support it in proper taking off position. This basket is shown as being made of angle iron, reinforced by diagonal braces 9, 10, and provided with a downwardly extending rest 11 and with a carrying loop 12, preferably braced by a small cable 13 extending from it to the basket. At

the rear of the basket is mounted a releasing Serial No. 292,115.

mechanism which is shown as consisting of a catch 14 pivoted at 15 to the frame work of the basket and having a counterbalance weight 16 sufficiently heavy to normally throw the hook of the catch up.

Below the catch 14 a keeper 17 is pivoted at 18 to the frame of the basket, and is also provided with a counterbalance weight 19 sufficiently heavy normally to throw the opposite end of the keeper up. A check rope 20 is fas tened to the end of the keeper 17 and extends down to the fuselage of the air plane where it can be reached by the pilot; or it may be eX- tended to a point free of the airplane if it is desired that the catch shall be released by someone not in the airplane. From the girder 3 a cable 21 is stretched to the top of a post 22, and from this cable is suspended a sheave 23 over which runs a cable 24, which also runs over a sheave 25, near the top of 7 the pole 22, and thence down to the drum 26 of a hoisting engine 27 mounted near the foot of the pole. This hoisting engine may be of any approved type. So I consider it unnecessary to illustrate the details of its construction.

The other, or free, end of the cable 24 is provided with a loop 25 which is adapted to re ceive the free end of the catch 14 as illustrated in Figs. 4 and 5. Then the loop 25 is fastened to the catch 14, the basket 8, with an airplane attached, may be swung backward and upward as illustrated in Fig. 3 by winding the cable 24 around the drum 26 of the engine 27, and when the check rope 20 is 5 pulled downward, the keeper 25 will release the catch 14, allowing it to slip out of the loop 25 so that the basket 8 and the airplane may swing downward and forward in the position shown in Fig. 2.

In or on the fuselage of the airplane 43 is mounted a carrying device which consists essentially of a hook 30 pivoted as at 31 to a frame element 32 attached to the fuselage of the airplane. This hook 30 is counterbalanced by a weight 33, so that the point normally rises.

A keeper 34 is also pivoted to the framework as at 35 and is extended into an arm 36. Normally the keeper tilt-s upward so as to e11- The length of this check rope 39 and its adjustment is such that when the airplane has reached the take-off position in its downward and outward swing, for instance, as shown in Fig. 2, the check rope 39 will become taut between the arm 36 and the cleat ll, and the continued swing of the basket 8 and airplane will cause the keeper 3st to be sprung 20 free of the hook 30 by the drag on the choc rope 39, and the increased drag on the rope Wlil separatethe members of a conventional bell cord coupling it, so that one end of the rope will remain attached to the arm 36, while the other end will remain attached to the pole. When the hook 30 is released by the keeper 3d, it will free itself from the loop 12 and thus free the airplane from the basket, thi being accompanied by separation of the bell cord coupling 44 as the airplane contin use its forward movement, as already pointed out.

This check rope 39, as will be seen, is in the nature of a safety line which will automatically release the ai ne from the sling basket in case the pilot should omit to do so. However, this safety check rope 39 may be disconnected, if desired, or it may be operated by hand fromthe ground or by automatic means.

. To give stability to the airplane in its connection with the sling basket 8 I provide a suitable stop 42 secured to the framework of the fuselage, and adapted tocooperate with the rest 11 so as to prevent the tail of the airplane from dropping down, out of proper position in its'relation to the basket 8, the

air lane bein nreferabh balanced so that l: I.

there isaslight inclination of the tail to drop when theairplane is suspended from the basket 8,

In order to raise the airplane to a position where it willswing free of the ground, suitable elevating means are provided, such as air-elevator 45, which i indicated as having its platform 46 substantially level with the surface of the ground. The airplane may be rolled upon the platform and then raised by the elevator to a position where proper connection can be made with the sling basket 8, after which the elevator can be lowered away from the plane. As the mechanism of this elevator ma be'of an a 3 aroved pattern. and

.l J A.

as I do not .claim noveltyin the details of the construction of the elevator, it is unnecessary hoisting to describe the details of this mechanism, but

I have indicated a platform elevator having a piston 47 below the head 48 of which compressed air or the like may be forced by any suitable means to raise the platform elevator.

In practice, an airplane is mounted upon the elevator platform and raiser so that the hook 230 may be passed through the loop 12 and held in position by the keeper 34-, and the elevator is then lowered away from the airplane. The catch l l is passed through the loop 25 and locked in position by the keeper 17. The sling basket 8, carrying the airplane, is then drawn backward and upward toward the sheave by the hoisting engine 27' rolling up the cable 2st on its drum 26. The airplane is then in position for launching. Its engine'may then be started. Vfhen satisfactory speed has been developed, the pilot may pull the check rope 20, thus freeing the catch 14 from the loop 25 and allowing the sling basket and the airplane to swing downward and forward, its movement being accelerated by the pull of the propeller. This pml of the propeller, aided by the swinging movement under the force of gravitation, will, if the apparatus has been properly proportioned, develop sufiicient speed when the airplane is passing the lowcst point of its swing to enable it to support itself in flight. At this instant the pilot may pull the check rope 38, thus freeing the catch 30 and releasing the airplane from the sling basket 8, or release may be effected auton'iatically through the check rope 39 operating as above described. The airplane, being thus freed from the sling basket, proceeds on its light while the sling basket will gradually swing back to its former position above the elevator.

I desire it to be understood that the particular means which I have illustrated and described for suspending and releasing the airplane may be modified, as by the use of mechanical equivalents, without departing from the spirit of my invention, for it is obvious that the release of the carrying means and means might be accomplished through mechanical apparatus instead of hand controlled apparatus, and various other modifications might be made.

Having thus described my invention, what I claim and desire to secure by Letters Patent of the United States is 1. In an airplane launching apparatus, the combination of optionally releasable swinging means for suspending the airplane, releasable hoisting means for swinging the suspending means backward and upward, means for releasing the hoisting means, and means for releasing the airplane from the suspending means.

2. In an airplane launching apparatus, the combination of optionally releasable swinging means for suspending the airplane, means for elevating the airplane to connect with the swinging means, releasable hoisting means for swinging the suspending means backward and upward, means for releasing the hoisting means, and means for releasing the airplane from the suspending means.

3. In an airplane launching apparatus, the combination of optionally releasable swinging means embodying cables sustaining a unitary element for suspending the airplane, releasable hoisting means for swinging the suspending means backward and upward, means for releasing the hoisting means, and means for releasing the airplane from the suspending means.

4. In an airplane launching apparatus, the combination of optionally releasable swinging means for suspending the airplane, releasable hoisting means for swinging the suspending means backward and upward, releasing means extending from the airplane to the releasable means, means for releasing the misting means, and means for releasing the airplane from the suspending means.

5. In an airplane launching apparatus, the combination of optionally releasable swinging means for suspending the airplane, releasable hoisting means for swinging the suspending means backward and upward, means for releasing the hoisting means, and means operable from the airplane for releasing the airplane from the suspending means.

6. In an airplane launching apparatus, the combination of optionally releasable swinging means for suspending the airplane, releasable hoisting means for swinging the suspending means backward and upward, means for releasing the hoisting means, and automatic means for releasing the airplane from the suspending means.

7. In an airplane launching apparatus, the combination of a pair of towers, a carrying member connecting the towers, cable suspended from the carrying member, an airplane carrying element supported by the cables, releasable connecting means between the carrying element and the airplane, means for elevating an airplane to connect with the carrying'element, hoisting means embracing a cable, a Windlass and means for turning the Windlass to hoist the carrying element and airplane backward and upward, and means for releasing the airplane from the hoisting means to permit the forward swing of the airplane.

8. In an airplane launching apparatus, the combination of a pair of towers, a carrying member connecting the towers, cables suspended form the carrying member, an airplane carrying element supported by the cables, releasable connecting means between the carrying element and the airplane, means for elevating an airplane to connect with the carrying element, hoisting means embracing a pole, a cable connecting the pole and the car- 

